Speedometer-drive reducer



May 14, 1929. E. A. GUSTAFSON SPEEDOMETER DRIVE REDUCER Filed June 5, 1926' 2 Sheets-Sheet 1 gwwwtor y 14, 1929- E. A. GusTAFsoN 1,712,955

SPEEDOMETER DRIVE REDUCER Filed June 5, 1926 2 Sheets-Sheet 2 l atenteel May 14, 1929.

NITED STATES PATENT lEZlJ'WlI-I GUSTAFSON, OF FLINT, MIGJEIIGAN, AEJSIGNOR TU A. G SHARK Plifili'br COM- PANY, U]? FLINT, MICHIG-AII, A CUll'lPANE. OF IVIHJI'IiTTLGAN. 4

fi'PEEDOMETlER-DRIVE RliiDUGER.

Application filed June 5, 1.926.

This invention relates to transmission mechanism and. in its broader aspects, is intended to allord convenient means for securing a plurality of driving ratios between a driving and. a driven member.

The expedient is herein shown as applied to a driving connection between a shaft takint;- oil power from the conventional. transmission of a motor vehicle and the flexible drive shaft for operating the speedometer. it will be understood, however, that the invention has utility in other relations. It freipiently l'iappens that the gear ratio between the transmission shaft and the speedometer sha'it must be cm'i'ected, owing to changes which have been made in the sizes oi tires or in the rear end driviir; ratio. In the or so oil? some trucle-s, several different sizes of tires are used, as are also a number of dil'l'erent gear ratios. To accommodate these di'l'lerences it has been necessary to provide means for changing the gear ratio between driving shaft and the flexible speedometer shaft.

Among the objects of the present invention the primary pi'lrpose is to secure in compact assembly a structure for melting use of pluralv gear ratios between a driving sh att and a driven shalt. it secondv object is to so construct a secondary gear housing as to permit a substitution oil with the attainment of varying gear ratios. Other advantages and objects will be obvious upon a reading ot the following s iieciiieation and an examination ol the arcon'ipanying drawin in the drawing:

Figure 1 is a transverse section through a supplementizl transmission housing showing my invention applied.

Figure 2 is a section on line 2-2 of Figure 1.

Figure 3 is a plan view of a part of a device.

Figure l is a section online il- 1 of Figu re 1.

Figure 5 is a view similar to Figure 1 but showingn'iodil'ied form.

lligure (3 is a sectiiini on line 6-ti oil Figure 5.

l igure 7 is a section on line 2'--7 of Figure 5.

l-leilierringr by reterence characters to the drawing. numeral. 1 is a supplemental housiine oi? son'iewhat tubular shape. it has a flange 3 by which it is secured to the transmission housing 5 with the aid of fastening means i. llHthin the supplemental housing 1 is a blaring 9 rotatably supporting the drive Serial N0. 113,897.

shaft 11 which extends from the transmission housing. At its other end the supplemental housing 1 is provided with a closure 13 carrying packing l l around its central openingthrough which passes the shaft 11. Between the bearing 9 and the closure 18 there is keyed, as at 1.5, to shaft 11 a driving gear 17. This driving gear 17 is intended to serve a means tor driving the flexible shaft on the specdoineter.

Extended transversely across said supplemental housing at one side of shaft 11 is a driven shaft 19. One endv oi shalt 19 is re duced and has a bearing in a recess 21 in a plug 23 which is threaded into the supplemental housing. The other end oi Slltlllii ll) also reduced and rotates in an opening; provided therefor in the tubular member as shown at 25. l l ithin the supplemental housing ll'iUlllif/(l' the shaft 1!) is provided With a driven gear in the vicinity oi the en d oil? shaft 19 the member 1 is formed with a relatively large circular recess 29, this recess to serve as a near housing. The shaft 19 extends eccentrically into the recess, and upon its outer end is provided with a pinion 31. .th nut 32 used to hold the pinion in place.

A cover 233, cirmilar .in tiniin, has a slightly reduced part 34: extending into recess 29 and may be rotatedv about the common axis of the recess and cover. To secure the cover in adjusti-id position its outer periphery is provided with a plurality oi? irregular spaced semhcircular grooves 35, any one oli which may be placed in registration with a circular pin 39 in part i.

The cover has an upstanding threaded sleeve portion 11. to which is to be connected the flexible housing o'l an ordinary speedo1neter shaft. Extending through said part 4-1 is a shaft l -l. it will also be seen that shaft i3 enters the recess 2i) in an eccentric position relative to the common center of the recess and cover, and that it is provided \vi th. a gear 4-5) which meshes with pinion 31. The gear may be held. in place by a nut 50. The shatt 43 has a suitable opening 51 to receive connectinp means carried by the flexible speedometer shalt whereby the shaft 413 enabled to drive an d. operate the speedometer. A pair oi: screws 53 are threaded into part 1 and enn'age the edge of cove r 33 to secure it in position.

It is the purpose of the invention to provide iii) different gear ratios between the shaft 19 and shaft 43. To that end gears of different sizes may be substituted for gear 49, each of which is to be in driving engagement with pinion 31. The relative rotation of cover 33 and the eccentric positions of shafts 19 and 43 have been arranged to render such substitution possible. Since the position of shaft 19 is fixed .and is eccentric relative to the common center of the housing and cover, and since shaft a3 is rotatable about the common center, it will be seen that by rotating the cover an opportunity is afforded for substituting gears of va rious sizes in place of gear 49 with av consequent change in driving ratio between the shafts. There is in this way secured to plurality of definite positions of the cover and'housing for each of the plurality of gear sets. To make the change in the driving ratio to accommodate the change in sizes of tires or other parts it is merely necessary to substitute for gear 49 a gear of suitable size, to rotate the cover 33 to its proper position and to thereafter secure the cover in position.

In Figures 4 and 5 is shown a slight modification of the structure illustrated in Figures 1 to 3. In this figure the shaft 11 and shaft 19 are mounted just as in the form already described. In this modified form the supplemental housing is formed partly by an annular member 61 secured by fastening means (33 to the supplemental housing 1, and by the cup shaped member 65. The annular member 61 has a number of notches 64, any one of which is engageable with the lug 67, on the lower edge of the cup 65. A ring 69 engages the shoulder near the lower edge of the cup and through this ring screws 71 may be inserted to engage in the housing member 1.

IVithin the supplemental housing the end of shaft 19 is provided with an annular ring gear member 73, the gear member being held by a screw 75. Engaging with said gear member 73 is a driven pinion 77 secured to the inner end of driven shaft i3. In this case, as in that already described, when the cup shaped member 65 is rotated about the common axis of the recess and cover provision is afforded for the substitution of other gears in place of gear 77 to thereby change the driving ratio between ring gear 7 3 and driven pinion 77.

In each of the two forms shown a very convenient arrangement has been provided by which the gear ratio for driving the speed.- omcter shaft may be readily changed. In each case it is merely necessary to remove a cover member, substitute one gear for another and turn the cover to a suitable position o f adjustment.

I claim:

1. A power transmission mechanism comprising a gear housing, a cover therefor, a shaft eccentrically journaled in said housing, a second shaft eccentrically journalcd in said cover, said cove and housing being relatively rotatable about their common center, and interchangeable gearing between said sha l'ts within said housing.

2. A power transmission device comprising a casing and a concentric cover of equal radius therefor, the casing and cover being arra nged for adjustment circumferentially about their common center, a shaft ecccntrically mounted in the casing, a second shaft cccentrically mounted in the cover, gearing clemen t s engaging each other within the casing and secured to the shafts, the adjustment of the casing and cover permitting substitution 0 f gear elements and change of gear ratios.

3. A casing having an internal gear mounten eccentrically therein, a cooperating concentric cover member of like radius having a. spur pinion mounted ecccnt'rically therein, the casing and coverbcing relatively rotatable about their common center and having intcrengaging parts to hold them in a plurality of: circumfercntially spaced positions corresponding to the engagement of the internal gear with the plurality of pinions, the gear and the pinion being mounted on sha l'ts rotat able in their respective casing elements.

4. In a transmission device, a cup and a. concentric cover, shafts cccontrically positioned in each, said cup and cover being relatively rotatable about their common center, one of said shafts having a gear within the cup, means to secure the cup and cover in a. plurality of circum'l'erentially adjusted positions, each positioned determining the cugagement of a definitely selected pinion on one shaft with the gear on the other sliaft.

In testimony whereof I a'liix my signature.

EDWIN A. GUSTAFSON. 

